.content-box {
    position: absolute;
    left: 203px;
    right: 0;
    top: 100px;
    bottom: 0;
    overflow-y: scroll;
    -webkit-transition: left .3s ease-in-out;
    transition: left .3s ease-in-out;
    background: #f0f0f0;
  }
  .content-collapse {
    left: 55px;
  }